Sorry, "psl" is Peter S. Langston, so:
https://en.wikipedia.org/wiki/Empire_(1972_video_game)
http://www.langston.com
That Wikipedia entry should describe it as a "computer game" (or
"simulation") rather than as a "video game", given the common
understanding of those phrases. PSL's "empire" was a multiplayer game
similar (sort of) to the board game "Risk" and the "graphics" were
ASCII-maps.
I played that game at some length after leaving UCB - it was "guaranteed to drop your
GPA two points" (addictive as hell). Another way to parboil your brain with it was to
set the "update interval" to 5 seconds (a.k.a. a "flash" game) and
have a several hour (instead of the more typical several month) gaming session with
like-minded crazies ... I mean, "players" ... in a terminal room.
I recall one such evening up at LBL with Craig Leres and Jef Poskanzer, among others ...
Anyway, the Dave Pare mentioned in the Wikipedia entry is the same one who worked on
decompiling the Morris worm, with the aforementioned tools he'd developed (he liked
playing empire and wanted to fix bugs and extend the game, but psl was only supplying
binaries ...).
It's funny where tools come from sometimes.
Erik